Obesity is a prevalent nutritional disorder in the United States. Obesity in childhood, adolescence, and adulthood represents a serious concern and a challenge to the medical and lay communities. Major impacts include effects on blood pressure, intermediary metabolism, respiratory function, psychological well-being, social adaptation, and educational performance. Obesity is associated with significant adult morbidity, including long-term effects on cardiovascular health and premature mortality.
Accumulation of excess fat mass occurs when total energy intake exceeds total energy expenditure, including the energy allowance for normal growth. This energy imbalance can result from excessive energy intake and/or reduced energy expenditure for body metabolism, thermoregulation, and physical activity. Increases in energy intake are observed in genetic syndromes, such as Prader-Willi syndrome, Cushing syndrome, and drug-induced obesity. Reductions in energy expenditure characterize hormonal deficiency states, including hypothyroidism and growth hormone deficiency.
The etiology of obesity is considered to be multifactorial. Animal obesity has been classified into nine different groups, including obesity of neural, endocrine, pharmacological, nutritional, environmental, seasonal, genetic, idiopathic or of viral origin (see, e.g., Sclaffini, A. (1984) Int. J. Obesity 8: 491-508; herein incorporated by reference in its entirety). While genetic and behavioral components of obesity have been the focus of intense study, six pathogens have been reported to cause obesity in animal models (see, e.g., Atkinson R. L., et al., (1997) Int. J. of Obesity 21:S36; Carter J. K., et al., (1983) Infect. Immun. 39:410-422; Carter J. K., et al., (1983) Avian Dis 27:317-322; Dhurandhar N. V., et al., (1990) J. Bombay Vet. College 2:131-132; Dhurandhar N. V., et al., (1992) Vet. Microbiol. 31:101-107; Dhurandhar N. V., et al., (1996) Obesity Res 4:24S; Dhurandhar N. V., et al., (2000) Int. J. Obesity 24:989-996; Gosztonyi G., et al., (1995) Current Topics in Microbiol. Immunol. 190:39-73; Lyons M. J., et al., (1982) Science 216:82-85; each herein incorporated by reference in their entireties). Indeed, the human adenovirus Ad-36 is implicated in causing obesity in humans (see, e.g., Atkinson R. L., et al., (1998) Int. J. Obesity 22:S57; Dhurandhar N. V., et al., (1997) FASEB J 3:A230; each herein incorporated by reference in their entireties).
Treatment options for virally induced obesity is limited to traditional approaches (e.g., diet management, exercise management, lifestyle management, surgery, and anorectic agents (e.g., phentermine, phenylpropanolamine, mazindol, ephedra, and sibutramine)). What is needed are improved methods of treating obesity.